Conventional semiconductor stacked bodies containing group III-V compound semiconductors can be used to produce light-receiving elements that can receive infrared light. Specifically, a light-receiving element for infrared light can be produced by, for example, sequentially stacking a buffer layer, a quantum-well light-receiving layer, and a contact layer, each of which contains a group III-V compound semiconductor, on a substrate containing a group III-V compound semiconductor, and further forming suitable electrodes. Such a light-receiving element has been reported to be a photodiode with cutoff wavelengths from 2 μm to 5 μm (see, for example, Non Patent Literature 1).